Alternating A/B week timetable: decide what a holiday skips
A two-week recurrence keeps counting calendar weeks even when a class is removed. If a school pauses its A/B rotation during a holiday, deleting the holiday’s lessons alone will not create the intended post-break timetable. Confirm the school’s published schedule first.
Monday-only worked timetable, November–December 2026
| Monday | Unchanged two-week phase | Fixed cadence after removing break | Paused cycle |
|---|---|---|---|
| Nov 2 | A | A | A |
| Nov 9 | B | B | B |
| Nov 16 | A | A | A |
| Nov 23 | B | Break: remove occurrence | Break: pre-break series ended |
| Nov 30 | A | A | B: fresh post-break series |
| Dec 7 | B | B | A: fresh post-break series |
| Dec 14 | A | A | B |
| Dec 21 | Outside teaching block | No class in this example | No class in this example |
Two recurrence patterns, one policy question
RFC 5545 can express weekly recurrence with INTERVAL=2. Outlook’s guide explicitly gives an every-other-Monday example. Google documents choosing the repeat frequency and ending date. The particular school decides whether a holiday consumes a rotation week; the calendar standard does not.
For this fictional Monday-only class example, A starts November 2, 2026 and B starts November 9. Both repeat every two weeks. November 23–27 is a chosen one-week break, and the example’s second teaching block ends December 18. This is not a real school holiday calendar.
Fixed calendar cadence: remove the break, keep the phase
With no re-anchoring, A would occur November 2, 16 and 30, then December 14; B would occur November 9 and 23, then December 7. Removing B on November 23 leaves November 30 as A.
RFC EXDATE removes matching recurrence instances; it does not restart the two-week interval. A provider’s single-occurrence deletion can implement an exception without literally exposing an ICS file, so verify the resulting dates in the source account.
Paused teaching cycle: bound and restart deliberately
If the school instead requires November 30 to be B, bound the pre-break series to the final teaching date before the break, then create post-break B on November 30 and A on December 7, each repeating every two weeks through December 18. Inspect for duplicates from any old unbounded series.
Use the editor’s supported ending-date control. If generating raw ICS, UNTIL has value-type and UTC requirements depending on DTSTART; do not write a placeholder such as UNTIL=Nov 20. The COUNT/UNTIL guide explains those requirements.
For classes on several weekdays, create the actual weekday/time records, not a single Monday class and an assumption that the rest appear. Use the published timetable to verify each one.
Verify the first two teaching weeks after every break
In the fictional example, fixed cadence produces A on November 30 and B on December 7. A paused cycle produces B on November 30 and A on December 7. That pair of dates is a more reliable check than a vague label such as odd week.
An even two-week break preserves the phase difference under these two explicitly defined models; an odd one-week break changes it. Partial-week closures, day rotations and school-specific resets need their own published rules.
What it looks like
Cloud Calendars overview, using our product images. Provider settings and protocol examples described in this guide are separate from the screens shown here.
What to do
- Read the school’s actual first post-break timetable.
- Choose the intended cadence before creating series.
- Bound old series before re-anchoring to avoid duplicates.
- Verify the first two post-break teaching weeks.
Questions
- Why does deleting the break not swap A and B?
- An excluded occurrence does not reset the recurrence interval. Restart at the intended post-break anchor if that is what the school publishes.
- Can every school use the same two-week rule?
- No. A day rotation, partial-week closure or school-specific reset can follow a different policy. Use its official timetable.